Briquetting asphalt composition and process of making same



Vit. tion and to the method of United States Patent BRIQUETTING ASPHALT COMPOSITION AND PROCESS OF MAKING SAlVlE Mathew L. Kalinowski, Chicago, 111., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application February 27, 1951, Serial No. 213,055

4 Claims. (Cl. 196-42) This invention relates to an improved asphalt composiits manufacture. The invention refers particularly to asphalt compositions having increased compressive and cohesive strength, and, because of this increased strength, greater suitability for briquetting purposes.

The widespread employment of cracking processes in petroleum refining supplies a large volume of asphaltic residues which yield asphalts that are useful as binding agents in aggregate compositions, an important one of which is solid-fuel briquettes. However, these cracked petroleum asphalts as a class are often too brittle or in some other strength characteristic do not meet specifications defining briquetting agents of suitable binding strength. A primary object of the present invention is therefore the provision of an asphalt composition having improved strength characteristics. Another object of the invention is the provision of a method of preparing improved asphalt compositions. Yet another object of invention is the provision of an improved briquetting asphalt.

I have found that the foregoing objects can be accomplished by the incorporation in the asphalt of the treated by-product of a well-known process of chemical petroleum refining of lubricating oils. In this chemical-refining process, lubricating oils, which may previously have been dewaxed, are extracted with phenol or phenol homologs to remove undesirable constituents. The extraction of these constituents, which include petroleum resins and aromatic compounds, results in increasing the viscosity index of the oils as well as efiecting other improvements. The phenolic solvent can be recovered from the extract by any one of several known methods including, for example, steam distillation. The phenol-free, undesirable constituents of lubricating oils, obtained by the phenol extraction process described briefly above, are hereinafter referred to as phenol extract.

Briefly stated, the present invention comprises the method of, and the asphalt composition provided by, extracting a phenol extract of a lubricating oil with a hydrocarbon solvent consisting of one or more paraifinic hydrocarbons having more than one and less than about eight carbon atoms per molecule and being preferably a normally gaseous hydrocarbon, thereafter separating a resinous, raflinate phase and extract oils phase, removing solvent from the resinous rafiinate phase, and incorporating in preferably a cracked-petroleum asphalt from about 5 to 25 percent, by weight based on the asphalt, of solvent free resins from the said raffinate phase. Compositions containing any petroleum asphalt and an amount, within the said range, of the extract resins will provide suitable briquetting asphalts. However, the invention is especially applicable to cracked-petroleum asphalts and to improving the strength characteristics of these asphalts for use as binding agents. Cracked-petroleum asphalts are obtained by the reduction of tars from cracking processes. These asphalts are usually air-blown at elevated temperatures to a softening point of between about 150 and 200 F. The said solvent-free resins constitute primarily petroleum resins characterized by a melting point between about 80 and 120 F., a specific gravity between about 0.85 and 0.95 at 77 F., and a color as determined by the ASTM method 115-45T of about 8. The rafiinate will also contain minor quantities, at most about 35 percent, of waxlike material as determined by ASTM method D-72l47; this method may report as wax some of the aforementioned resins. This minor content of waxy material will,

2,702,266 Patented Feb. 15, 1955 of course, be substantially eliminated when the lubricating oils are dewaxed before extraction with phenol.

in the preparation of the said phenol extract, a distillate oil is obtained by the distillation in fractionating equip ment of a reduced crude petroleum. The reduced crude can he fractionated, for example, into such lubricating oil types as SAE 10, 20 or 40. This oil is usually not de waxed before phenol extraction because sufiiciently high temperatures are employed during extraction to prevent precipitation of the wax during the extraction step. The phenol extraction is preferably carried out in a countercurrent multi-stage operation equivalent to about five to seven stages using from 2 to 4 volumes of phenol for each volume of oil and employing temperatures between about 160180 F. at the top of the extraction tower and 140l60 F. at the bottom thereof. Water is preferably injected into the extraction mixture near the bottom of the tower to improve the selectivity of the phenol extractant. The degree of extraction obtained is directly reflected in the viscosity index of the treated oil, more intense treatment resulting in higher viscosity indexes. The phenol can be removed from the extract by any of the known solvent reclaiming methods and preferably by the method of fractional distillation and steam stripping described and claimed in Sullivan U. S. 2,111,822 patented March 22, 1938.

The phenol extract, that is obtained by separation of the phenolic solvent from the extract, is then treated according to the hereinafter described method with a hydrocarbon solvent consisting of one or more parafiinic hydrocarbons having less than about eight carbon atoms per molecule, or between two and seven carbon atoms per molecule, inclusive, and preferably with a lower molecular weight hydrocarbon within this class.

When a normally gaseous hydrocarbon such as propane is used as the hydrocarbon extractant, the phenol extract is treated under propane deresining conditions. For example, propane and phenol extract are mixed at about F. in a ratio of about 8 volumes of propane for each volume of phenol extract, the mixture .is then heated to a temperature in the range of about F. to F., at which temperature autogenic pressure is about 350 pounds per square inch and separate phases of propane extract and propane raffinate are formed. The propane extract and propane rafiinate are separated, propane is stripped from the heavier raflinate phase, and the remaining extracted resinous material constitutes the additive employed in the present invention.

When a normally liquid hydrocarbon is employed the phenol extract and the hydrocarbon are preferably separately cooled to a temperature below about 0 F., preferably between about 60 F. and 20 F., and, when hexane is employed as extracting solvent, to preferably about 40 F. The phenol extract and hexane are then introduced into an extraction zone in a proportion of about 2 to 10 volumes of hydrocarbon per volume of phenol extract. By an alternate method, the phenol extract and normally liquid extractant can be mixed before the cooling step, in which case they form a single mutually miscible solution. When cooled to a temperature of between 60 F. to 20 F. the solution forms a two phase system. When adequate extraction and settling is obtained, separation can be accomplished by siphoning off the supernatant extract phase.

Propane and phenol extract, which have been separately introduced into a vertically extending extraction zone, are passed counter-currently through the said zone and will be separated one from the other in settling zones at the opposite ends of the extraction zone. The propane extract that is removed from the top of the extraction zone is then stripped of propane by releasing the pressure. The recycled propane is cooled, condensed and can be recycled to the extract step. The extract remaining after removal of the propane consists of the oil components of the treated phenol extract, which components usually comprise about 70 percent by weight of the total phenol extract.

The propane raflinate that is separated by either decanting the propane extract from the surface of the liquid or by the above described countercurrent operation is stripped of propane by release of pressure, the propane that is disponents'of the lubricating oil.

flashing phenol from about 30'percent as resinous oil.

solved in the ratlinate solution being permitted to escape therefrom. The released propane can be cooled, condensed, and recycled to further extraction.

The reduced ralfinate contains the said petroleum resins and a minor quantity of wa Yields of resins ranging from about 10 to 40 percent by weight of the phenol extract have been obtained.

Pressure-still asphalt and about 2 to 25 percent by weight of the phenol-extract resins are thoroughly mixed at a temperature between about 200 and 400 F. and at preferably about 300 F. Coal briquets consisting of coal fines and a small amount, preferably between 4 to 8 percent by weight, of the asphalt briquetting composition show good strength and stability.

It has been found that the total phenol extract is not effective as an additive to provide a briquetting asphalt, and that asphalts incorporating the total extract are not satisfactory briquetting agents. The light-hydrocarboninsoluble resinous fraction of the phenol extract is, on the other hand, effective to improve the binding characteristics of asphalt as demonstrated in the following specific examples.

EXAMPLE I Lubricating oils in the threegrades SAE 10, 20 and 40 were obtained by distilling, under vacuum, a .reduced Mid-Continental crude oil from Which 62 percent of the lighter ends had previously been removed These distillate oils contained wax to the extent of weight percent for the SAE distillate to about 9 weight percent for the SAE 40 distillate.

The three lubricating oils were each treated with a phenol extractant in a countercurrent multistage-operation in which'about 2.5 volumes of phenol were used for each volume of oil. The temperature of the extraction mixture was about 160 to 180 F. at the top'of the extrac tion tower andabout 140 to 160 F. at the bottom thereof. Water in the amount of 5 weight .percent of the phenol was injected nearthe bottom of the tower to improve the selectivity of the phenol for undesirable com- 7 Operation of the extraction unit was adjusted carefully to obtain certain viscosity indexes for each grade of oil. The phenol was substantially entirely removed from the phenol extract'by first the extract material and then steam stripping to remove the remaining phenol from the extract. The yields of phenol extract ranged between about 40 and 45 percent.

About one part of phenol extract from each of the distillate oils was each dissolved in five parts of hexane and the solutions were cooled to about -40 F. At this temperature a two phase system was formed and separation was cfiected by siphoning off the supernatant ex traction phase. Thishexane extraction accomplished a distribution of the phenol extract in the proportion of components in the raifinate phase and about 70 percent as-oils in the supernatant extract phase. After separation of the phases and subsequent removal of hexane by 'flash distillation of this light solvent from the rafiinate phase, the resin fraction of 'a phenol extract was obtained. There were obtained from the said lubricating oils, SAE 10, and 40, resin yields respectively, of 31, 10 and 20 weight percent. These phenol'extract resins exhibited the properties outlined in the following table:

Table I.Physical propertiesof phenol extract resins Color Resin from ASTM 3 3?" Dar-42 c F 155l5T SAE 10 Phenol Extract 86 0.90 8+ SAE 20 Phenol Extract 115 0. 88 8+ SAE 40 Phenol Extract 116 0.87 8+ A briquetting asphalt composition was prepared by cent by Weight based on the asphalt of theabove prepared resin fraction of phenol extract of SAE l0 lubricating Thiscompo'sition was prepared by heating and stir- 'ri'ng asphalt ata' temperature of about 300. F. while adding the describedresin component. asphalt .was

also blended with 25 percent by weight of each of the resin extracts of SAE 20 and SAE 40 oils.

A portion of the total phenolextract' (without hydrocarbon solvent extraction) from SAE 10 oil, equal in weight to the above employed weight of resin extract from SAE 10, was added to a proportionate weight of the same asphalt and mixed therewith at the same temperature. The total phenol extracts of the other oils were also blended with samples of the same asphalt at the same temperature.

Briquetting asphalts consisting of the untreated asphalt and compositions containing 18% of the total phenol extract in some cases and 18% of the extract resins in others were mixed with fine coal in the amount of 6% by weight of asphalt based on the weight of the coal, and the mixtures were briquetted under standardized conditions. The so-formed briquets were tested for compressive strength as reported in Table 2.

As shown in this phenol extract and the resinextract ,from phenol extract of an SAE 10 lubricating ail are compared, the total phenol extracts were ineffective as additives to provide a sutable briquetting asphalt.

Table 2.-Efiect on asphalt physical prgperties of phenol extract resin compared to total phenol extract site as B p a V rique mg pf i f Phenol Tutsi Asphalt Extract Phenol Requirements Resins Extract Softening Point, 175 135 130-140. Penetration at 77 2 1s 19 Between 15-20. Ductility at 77 FA. Shatters 100+ -18 min. 100. Specific Gravity... 1.13 1.07 1.09 .min. 1.06. Flash, F.-. O. O. C. 565 500 495 min. 450. Cohesive Strength Shatters. 100 71 min. 85.

of) Asphalt (p; s. 1. Compressive l35 225. 181 min. 200.

Strength (Lbs). x i

K Ductility as determined by ASTMtest D 11344.

2 Cohesive strength is a pressureirequired to shear a strip of asphalt one-half inch wide by one inch long and 0;010 inchi0.002 inch thick at a uniform rate of shear in a Perkin tensile tester manufactured by B. F.

Perkins and Son, Inc. of Holyoke, Mass.

It is to be observed in the above table that the asphalt compositions containingresinextracts in every case meet all the requirements of the briquetting asphalt specifications listed in the above table. It is further noted that the employment of the total phenol extract while lowering the softening point and increasing the penetration to the required extent failed toincre'ase ductility, cohesive-or compressive strength to a degree needed to provide an acceptable briquetting asphalt. Theimprovement provided by the extract, resins was obtained without so altering the characteristics of the asphalt as to render it, in some other respect, unsuitable for 'coal briquetting. This characteristic of the extract resins is important because, While itmight 'be'expected that many oils could be blended withbrittle asphalt to plasticize it, such additives degrade strength characteristics and otherwise alter the asphalt and render -itunacceptable for binding purposes.

EXAMPLE II The resin. fraction of the phenol extract of an SAE 10 lubricatingoilwas obtained by mixing one part of the extract with'five parts of hexane and cooling the solution that formed .to '40 F. -A two phase system was formedand separation .was eifected by siphoning oil the supernatant extract phase. After removal. of the hexane by evaporation, the-desired resinous components ,wer recovered about 31 percentyield based onthe employed weight of phenol extract.

A cracked-petroleum asph lt having a softening point of F; was blendedwith 18 percent by weight of .the resin fraction ofi-phenol extract by heating and stirring the two components at' 300 F. In a similar manner, another portion of the same asphalt was blended with 18 "percent of'the untreated total phenolextract. 'When the untreated asphalt is subjected to the cohesive strength test described in Example I, it shatters. The asphalt composition containing the resin extract exhibited a cohesive strength of 100 pounds per square inch while the asphalt composition containing the total phenol extract had a cohesive strength of only 60 pounds per square inch.

EXAMPLE Hi When employing propane instead of hexane as a solvent, one part of a phenol extract of a lubricating oil is dissolved in 8 parts of propane under a pressure of about 350 pounds per square inch and at a temperature of about 150 F. At this temperature a two phase liquid system is formed, a supernatant extract phase containing oils from the phenol extract and a rafinate phase consisting of solvent and, predominantly, resins. The prases are separated by decanting the upper layer from the pressure vessel, and propane is removed from the lower resinous layer by releasing the product to atmospheric pressure. A briquetting asphalt having suitable ductility and cohesive and compressive strength can be prepared by mixing about by weight of the said resin with a pressure still asphalt and heating and stirring the said admixture at 300 F.

The improved asphalt composition provided by the present invention has been described primarily as a briquetting asphalt but of course the improved characteristics of the composition render it especially suitable for other binding purposes, and for use, for example, in floor tile or road making compositions.

Having described my invention, 1 claim:

1. An asphalt composition comprising a crackedpetroleum asphalt and a small amount of a resinous product that is obtained by the steps of extracting a distillate lubricating oil with a phenolic type extractant, separating the phenolic extract from the treated lubricating oil, stripping the phenolic extractant from the said extract, admixing the said extract and a paraffinic hydrocarbon containing less than eight carbon atoms per molecule, subjecting the mixture to a temperature at which it forms two separate liquid phases, one consisting of an oily portion of the said phenolic extract in solution in the hydrocarbon and another containing the resinous portion of the phenolic extract, separating the said liquid phases, removing hydrocarbon solvent from the so-separated resinous portion of the phenolic extract, and recovering the said resinous product therefrom.

2. The composition of claim 1 in which the amount of resinous product is in the range of about 5 percent to about percent by weight, based on the asphalt.

3. A method of preparing an asphalt composition suitable for briquetting, the said method comprising admixing an asphalt, that is obtained from the tarry residue of a cracking of reduced-crude petroleum, with from 5 to 25 percent, by weight of the said asphalt, of a resinous product that is obtained by the steps of extracting a distillate lubricating oil with a phenolic type extractant, separating the phenolic extractant from the treated lubricating oil, stripping the phenolic extractant from the said extract, admixing the said extract and a paratfinic hydrocarbon containing less than eight carbon atoms per molecule, subjecting the mixture to a temperature at which it forms two separate liquid phases, one consisting of an oily portion of the said phenolic extract in solution in the hydrocarbon and another containing the resinous portion of said phenolic extract, separating the said liquid phases, removing hydrocarbon solvent from the so-separated resinous portion of the phenolic extract and recovering therefrom the said resinous product, and heating the said asphalt and the resinous product to a temperature of between about 200 and 400 F. While stirring to obtain thorough mixing.

4. A method of preparing an asphalt composition that is suitable for briquetting, the said method comprising admixing from two to ten volumes of a parafiinic hydrocarbon having more than two and less than about eight carbon atoms per molecule with one volume of a phenol extract of a distillate lubricating oil from which extract the phenol has been stripped, subjecting the admixture to a temperature at which it forms an extract oils phase and a resinous rafiinate phase, separating the resinous phase from the oils phase, removing hydrocarbon solvent from the resinous phase, mixing a cracked-petroleum asphalt and from two to twenty-five percent, by weight based on the asphalt, of solvent-freed resins, heating the asphalt and resins and mixing the same at a temperature between about 200 and 400 F.

References Cited in the file of this patent UNITED STATES PATENTS 1,987,085 Thurston Jan. 8, 1935 1,989,045 Merrill Jan. 22, 1935 1,993,532 Skowronski Mar. 5, 1935 2,024,096 Dengler et al. Dec. 10, 1935 2,120,376 Shipp et al. June 14, 1938 2,317,150 Lovell et al. Apr. 20, 1943 2,455,709 Spelshouse et al. Dec. 7, 1948 

1. AN ASPHALT COMPOSITION COMPRISING A CRACKEDPETROLEUM ASPHALT AND A SMALL AMOUNT OF A RESINOUS PRODUCT THAT IS OBTAINED BY THE STEPS OF EXTRACTING A DISTILLATE LUBRICATING OIL WITH A PHENOLIC TYPE EXTRACTANT, SEPARATING THE PHENOLIC EXTRACT FROM THE TREATED LUBRICATING OIL, STRIPPING THE PHENOLIC EXTRACTANT FROM THE SAID EXTRACT, ADMIXING THE SAID EXTRACT AND A PARAFFINIC HYDRO CARBON CONTAINING LESS THAN EIGHT CARBON ATOMS PER MOLECULE, SUBJECTING THE MIXTURE TO A TEMPERATURE AT WHICH IT FORMS TWO SEPARATE LIQUID PHASES, ONE CONSISTING OF AN OILY PORTION OF THE SAID PHENOLIC EXTRACT IS SOLUTION IN THE HYDROCARBON AND ANOTHER CONTAINING THE RESINOUS PORTION OF THE PHENOLIC EXTRACT, SEPARATING THE SAID LIQUID PHASES, REMOVING HYDROCARBON SOLVENT FROM THE SO-SEPARATED RESINOUS PORTION OF THE PHENOLIC EXTRACT, AND RECOVERING THE SAID RESINOUS PRODUCT THEREFROM.
 3. A METHOD OF PREPARING AN ASPHALT COMPOSITION SUITABLE FOR BIRQUETTING, THE SAID METHOD COMPRISING ADMIXING AN ASPHALT, THAT IS OBTAINED FROM THE TARRY RESIDUE OF A CRACKING OF REDUCED-CRUDE PETROLEUM, WITH FROM 5 TO 25 PERCENT, BY WEIGHT OF THE SAID ASPHALT, OF A RESINOUS PRODUCT THAT IS OBTAINED BY THE STEPS OF EXTRACTING A DISTILLATE LUBRICATING OIL WITH A PHENOLIC TYPE EXTRACTANT, SEPARATING THE PHENOLIC EXTRACTANT FROM THE TREATED LUBIRCATING OIL, STRIPPING THE PHENOLIC EXTRACTANT FROM THE SAID EXTRACT, ADMIXING THE SAID EXTRACT AND A PARAFFINIC HYDROCARBON CONTAINING LESS THAN EIGHT CARBON ATOMS PER MOLECULE, SUBJECTING THE MIXTURE TO A TEMPERATURE AT WHICH IT FORMS TWO SEPARATE LIQUID PHASES, ONE CONSISTING OF AN OILY PORTION OF THE SAID PHENOLIC EXTRACT IN SOLUTION IN THE HYDROCARBON AND ANOTHER CONTAINING THE RESINOUS PORTION OF SAID PHENOLIC EXTRACT, SEPARATING THE SAID LIQUID PHASES, REMOVING HYDROCARBON SOLVENT FROM THE SO-SEPARATED RESINOUS PORTION OF THE PHENOLIC EXTRACT AND RECOVERING THEREFROM THE SAID RESINOUS PORDUCT, AND HEATING THE SAME ASPHALT AND THE RESINOUS PRODUCT TO A TEMPERATURE OF BETWEEN ABOUT 200* AND 400* F. WHILE STIRRING TO OBTAIN THOROUGH MIXING. 